“…The hydroxylamine intermediate, formed by oxidation of the secondary amine, if present, is rarely observed in vivo for piperazines or other nitrogen-containing alicycles. An explanation for this may be found in reports that this intermediate is inherently unstable (Beckett and Salami, 1972;Beckett et al, 1977;Franklin et al, 1977;Ziegler, 1987); however, identifications of stable alicyclic hydroxylamines have been made (Beckett and al-Sarraj, 1972;Achari and Beckett, 1983;Rodriguez and Acosta, 1997;Zhang et al, 2000). There are even fewer examples of glucuronic acid conjugation of alicyclic hydroxylamines in the literature (Straub et al, 1988;Delbressine et al, 1992;Schaber et al, 2001), and the structures of these metabolites have been largely deduced from mass spectrometry and in some cases 1 H NMR analysis.…”